NFC North: Training camp primer

What are some of the big question marks facing the Lions, Packers, Bears and Vikings with training camp just days away?

The Lions, Packers, Bears and Vikings are just days away from hitting the field for the start of training camp.

There's a ton of optimism in all four camps following free agency and the draft. All four teams got better this offseason, but no team is without its issues.

So, what is the biggest question mark for all four teams heading into training camp?

GREEN BAY

Issue: Can the Packers’ young defensive line grow up quick?

Twentyman’s take: The Packers were getting a little long in the tooth on their defensive front with Ryan Pickett (34) and Johnny Jolly (31). It was an aging unit that needed an upgrade for Green Bay’s defense to get better in 2014.

Datone Jones (Photo: Associated Press)

The Packers are getting younger and more athletic upfront with 2013 first-round pick Datone Jones (24) and third-year pro Mike Daniels (25). The Packers used a third-round pick on Khyri Thornton (24) and a fifth-round pick from last year, Josh Boyd, 24, will help the rotation.

It’s certainly a shift in philosophy for the Packers when 28-year-old nose tackle B.J. Raji is the old man of the group.

With youth comes growing pains, however, and how well that defensive front can come together early in training camp is something to keep an eye on in Green Bay.

Stats pack: Opponents converted third-and-short situations at an amazing clip against the Packers last season. The Packers allowed a conversion 74.4 percent of the time in third–and-less-than-four situations a year ago. The league average was 57.2 percent.

Quotable: "I like our young guys," defensive coordinator Dom Capers told the Green Bay Press Gazette of his new defensive line. "We've got a little different look to us on the defensive line from what we've had. Having B.J. inside as a nose tackle is going to be good, and we've got a lot of young guys we're looking at."

CHICAGO

Issue: Did the Bears pull the right strings this offseason on their defensive moves?

Twentyman’s take: The Bears are hoping a new scheme under coordinator Mel Tucker, along with a number of new faces, will bring dramatic improvement to a defense that finished 30th in points allowed last season.

They're expecting five-time Pro Bowl defensive end Jared Allen and free-agent prize Lamarr Houston to help improve their sack totals from a lackluster 31 in 2013.

They signed former Pro Bowl safety Adrian Wilson late this offseason and he’ll compete with Ryan Mundy and Chris Conte (when he returns from shoulder surgery) at safety. The Bears need to be better in the back end of their secondary.

At linebacker, will Shea McClellin’s move from defensive end to 4-3 outside linebacker go smoothly?

More than anything, however, the Bears need cornerback Charles Tillman and Lance Briggs to play young and to stay healthy. When they were lost to injury last year the Bears defense took a nosedive.

Stats pack: The Bears defense allowed a whopping 84 runs of 10-plus yards last year. To put that in a little bit of perspective, the NFL average was 47.

Quotable: “There’s a way to play football in Chicago and that’s to be tough and physical — set a vertical edge, violent-shed and run to the football,” head coach Marc Trestman told the Chicago Sun-Times this offseason. “We’ve go to practice that way every day to be the team we want to be.”

DETROIT

Issue: Is a revamped secondary an improved secondary?

Twentyman’s take: The Lions are putting a lot of faith in former second-round pick Darius Slay to be the man at cornerback this year.

Slay had an up-and-down season as a rookie, but played his best football at the end of the year. The Lions are hoping that upward trend continues right into training camp and he takes full advantage of his physical gifts.

Detroit is also putting faith in 34-year-old Rashean Mathis continuing to play like a 28-year-old Mathis.

In the backend, Glover Quin moves from strong safety to free safety. That move, coupled with the fact that he’s finally healthy after offseason ankle surgery, should allow him to be a playmaker back there.

The team went out and got veteran James Ihedigbo to pair with Quin. Having two veteran players in the backend of their defense, who have made their mark in this league by being reliable players, should help Teryl Austin’s new defense come together.

Stat pack: The Lions allowed 52 passes of 20-plus yards last season, which ranked in the middle of the pack at 15th. However, 12 of those completions resulted in touchdowns, which was the second most in the league.

Quotable: “Like most teams do in camp, you always have a couple turnover periods. If a receiver catches a ball we always go for the strip,” defensive coordinator Teryl Austin said. “If a running back comes through, we're always trying to poke the ball out. If the ball’s in the air, if we have an opportunity to intercept it without colliding and hurting our own player, we always try to make the catch.

“We don’t like to go for pass break-ups in practice. I always tell my guys to go for the interception now so you learn how to do it so when you get in the game it’s not the first time you’ve tried."

MINNESOTA

Issue: Is Teddy Bridgewater ready to take the reigns of the Vikings offense?

Twentyman’s take: Bridgewater’s draft stock dropped because of a terrible pre-draft workout, but the college tape on him doesn’t lie, and by all accounts, he was impressive during offseason workouts in Minnesota.

The Vikings re-signed veteran Matt Cassel this offseason and he seems to be the safe choice to start at quarterback Week 1, but Bridgewater is the future, and if he continues to play well, he might just force the Vikings’ hand by playing him.

The Vikings have terrific weapons at the skill positions. They simply need someone who can deliver those weapons the football on a consistent basis.

Stat pack: Vikings quarterbacks had an overall passer rating of 76.0 last season. The league average was 86.0 and the average among the 12-playoff teams last year was 96.4.

Quotable: "I think he probably should've gone in the first 10 picks," offensive coordinator Norv Turner recently told the team’s official website of Bridgewater. "He probably should've gone at least in the first half of the first round, and then we're sitting there with an opportunity to get him when we did, it was a bonus to me."